1. Field of the Invention
The present invention relates to a pre-exposing method for a photographic film, and to a manufacturing method for a lens-fitted film unit.
2. Description of the Related Art
There is a lens-fitted film unit as a kind of a camera. In the lens-fitted film unit, a simple photographing mechanism is included. This lens-fitted film unit is loaded with a photographic film and a film cartridge shell in advance. Such lens-fitted film unit is manufactured and merchandised by the assignee of the present application. Some of the lens-fitted film unit are loaded with a photographic film in which predetermined images are beforehand photographed by a pre-exposure. This pre-exposure is performed for a few frames of the photographic film, or for a part of the frame.
U.S. Pat. No. 5,546,146 discloses a pre-exposing method for performing a pre-exposure on a photographic film before the lens-fitted film unit is loaded with it. In this method, prior to loading the lens-fitted film unit, the photographic film is advanced frame by frame, and during the advancement, the pre-exposure is performed. After that, the lens-fitted film unit is loaded with the pre-exposed photographic film.
However, in the above-stated method, a process speed of the pre-exposure is slow. Thus, there arises a problem in that manufacturing efficiency of the lens-fitted film unit worsens because the lens-fitted film unit is loaded with the photographic film which is pre-exposed at slow speed.